The present invention relates to a device for locking and unlocking any member such for instance as a bar carrying bolts likely to co-operate with keepers, bolt-clasps or like bolt-staples or latch-catches for locking a door for instance.
Systems operated by an electric current for controlling lock bolts are already known.
It has thus already been proposed to fit doors with an electric keeper co-operating with a conventional bolt or spring-bolt. More specifically, the keeper is fitted with a small movable shutter or retainer which would retract or move aside under the action of the electric current and would release or disengage the bolt accordingly.
This system suffers from drawbacks. At first it would consume a certain amount of electric energy to the extent where the shutter or retainer of the keeper has to be kept electrically energized for some time necessary to the unlocking. Moreover, the locking of the spring-bolt within the keeper is not positive since this spring-bolt is acted upon by a simple spring and may therefore be easily picked and withdrawn from the electric keeper.
There are also locking and unlocking systems comprising a conventional bolt slidably mounted within a body and operated by an electromagnet allowing this bolt to move into and out of a keeper. This system however also exhibits the same kind of inconveniences.
As a matter of fact, the bolt which may consist of the core of the electromagnet would generally result in an electromagnet construction which is oversized and which has to be acted upon for a long time by the electric current to allow the bolt to move out of the keeper, thereby requiring a relatively substantial consumption of electric power. Furthermore, like the electric keepers, there is no positive locking of the bolt in the locked position so that is possible by means of a tool to readily actuate this bolt forming the core of the electromagnet in order to move the same out of its keeper. Finally and in case of a technical hitch resulting for instance from the bolt becoming jammed within the keeper, thereby preventing its retraction or also from the misalignment of the bolt with the keeper whereby its insertion into the said keeper would be prevented, it is understandable that the electromagnet would be kept energized by the user for a very long time in an attempt to nevertheless carry out the locking or unlocking operation which could lead to the electromagnet being damaged or even being put out of working order.